Greeke EE, et al. – An analysis was performed to examine the associations between overall and subscale scores of the Center for Epidemiologic Studies–Depression Scale (CES–D) and the Modified Fatigue Impact Scale (MFIS) as well as the longitudinal changes in scores in patients with multiple sclerosis (MS). Outcomes indicated that depression and fatigue in MS shared several features and had a similar longitudinal course. However, when cut–off scores were applied to define depression and fatigue, results indicated that non–depressed subjects with high fatigue might be at a greater risk for developing depression.

Methods

• This analysis consisted of MS subjects who completed a battery of patient reported outcome (PRO) measures including the CES–D and MFIS (N = 435).
• At the first available MFIS measurement, Pearson's correlation coefficient was used to estimate the association between the CES–D and MFIS in terms of both total scores and subscale scores.
• Linear mixed model was applied to estimate longitudinal change in each total score and subscale score.
• With the aid of Pearson's correlation coefficient and linear mixed models, the association between the measures in terms of longitudinal change was analyzed.

Results

• At baseline, 15% of subjects were classified as high on both depression and fatigue scales, 16% were classified as high on the fatigue scale only, and 9% were classified as high on the depression scale only.
• A high correlation between CES–D and MFIS total scores (r = 0.62) was observed.
• High correlations were also observed between the somatic and retarded activity subscales of the CES–D and each of the MFIS subscales (r ≥0.60).
• In terms of longitudinal change, the change over the first year between the CES–D and MFIS total scores showed a moderate correlation (r = 0.49).
• Subjects with high fatigue scores but low depression scores at baseline were more likely than subjects with low baseline fatigue and depression scores to develop high depression scores at follow–up.